The conformation of the non-collagenous (NC1) domain of the α3 chain of the basement membrane collagen IV [α3(IV)NC1] depends in part on phosphorylation. Goodpasture Antigen Binding Protein (GPBP) (WO 00/50607; WO 02/061430) is a non-conventional protein kinase that catalyzes the conformational isomerization of the α3(IV)NC1 domain during its supramolecular assembly, resulting in the production and stabilization of multiple α3(IV)NC1 conformers in basement membranes. Increased expression levels of GPBP have been associated with the production of aberrant non-tolerized α3(IV)NC1 conformers, which conduct the autoimmune response mediating Goodpasture (“GP”) syndrome. In GP patients, autoantibodies against the α3(IV)NC1 domain (“Goodpasture antigen” or “GP antigen”) cause a rapidly progressive glomerulonephritis and often lung hemorrhage, the two cardinal clinical manifestations of the GP syndrome. Furthermore, it has been proposed that GPBP regulates inflammation, apoptosis and protein folding, and that increased GPBP expression induces antibody-mediated glomerulonephritis (IgA nephropathy, systemic lupus erythematosus and Goodpastute autoimmune syndrome) and resistance of cancer cells to a number of chemotherapeutic agents including those (i.e. paclitaxel) inducing protein misfolding-mediated endoplasmic reticulum (ER) stress Thus, inhibitors of GPBP are useful for the treatment of antibody-mediated disorders, drug-resistant cancer, inflammation, protein misfolding and ER stress-mediated disorders, and aberrant apoptosis.